The present invention refers to a device for dispensing washing agents for a household washing machine, in particular a dishwasher.
As known, washing machines are usually fitted with a dispensing device of washing agents, namely powder and/or liquid detergents and additives; typically, the latter consist of softening media for laundry washing machines and rinsing aids for dishwashing machines.
In the instance of a dishwasher, the dispenser of washing agents usually comprises a body made from plastic material, partially built-in on one of the vertical surfaces delimiting the washing tub of the machine; in most cases, this vertical wall is the dishwasher inner door, i.e. the side of the machine front loading door facing inside the washing tub.
In its front area, the above body delimits a space for containing a detergent, usually in powder or in the form of a tablet, with a tilting or sliding cover; the opening of this small cover is appropriately controlled by a machine programmer or timer.
Inside the dispenser body a tank is provided, for containing a second liquid washing agent, typically a rinsing aid; in general, this tank has the capacity for containing a sufficient amount of liquid agent for several washing cycles, so that the machine user has only to fill the tank periodically, through a proper plug.
Inside the dispenser a small chamber is associated to the above tank, which is used for dosing the amount of rinsing aid to be dispensed during a washing cycle: to this purpose the dosing system of the rinsing aid exploits the opening-closing movement of the machine door, i.e. horizontal when open and vertical when closed, for supplying a portion of rinsing aid from the tank to the dosing chamber; during machine operation, the programmer operates an actuator to free a discharge outlet in correspondence with the dosing chamber, and let the amount of rinsing aid flow from the latter into the washing tub of the dishwasher.
As said, the known technique mentioned above requires the dispenser to be fastened to the dishwasher door, in order to exploit its opening-closing movement for dosing the rinsing aid required for a washing cycle; for this reason, the application of these dispensers is restricted on washing machines having a door tilting around a horizontal axis.
However, some known washing machines are not fitted with a tilting loading door, but the latter is linearly sliding on appropriate guides; with reference to a double-basket dishwashing machine, reference can be made, for example, to the solution described in FR-A-2.674.426; vice-versa, in other known solutions, the dishwasher has only one basket containing the crockery to be washed, which is designed like a sliding drawer with its front wall representing in fact the machine door.
Also in these machines the dispenser of the washing agents is fastened to the machine door or anyway to a wall or vertical surface delimiting the washing tub; as a result, the dispenser is always on the same resting plane, independently from the door opening-closing condition.
Therefore, the dispensers applied on such machines have to be equipped with a proper electric pump, of the vibration or peristaltic type, capable of dosing and dispensing the liquid washing agent; anyway, these pumps are relatively expensive, space requiring and difficult to control; moreover, these pumps may go out of calibration or become defective with time, also considering a certain corrosive capacity of certain liquid washing agents.
Other solutions provide on the contrary a special hydraulic circuit, able to convey water inside the device for dispensing the liquid washing agent and convey it into the machine washing tub; however, also these solutions are complicated, expensive and critical, considering that such an hydraulic circuit should be partially housed within the machine door.